AS11004 CITY-OF-GOLDEN-01

CITY-OF-GOLDEN-01 is the municipal network of the City of Golden, Colorado, the county seat of Jefferson County just west of Denver. ARIN registers the ASN to the city at 911 10th Street, Golden, with the city's IT department as the administrative contact.

What it's used for

This is a single-purpose local-government AS. RIS sees exactly 1 announced IPv4 prefix, 23.161.120.0/24, carrying 256 addresses, no IPv6, and 1 observed neighbour. That is the smallest routable footprint an organisation can have while still holding its own AS number, and the single upstream tells you why it exists: not to sell transit or to peer widely, but to let the city keep its own address space and re-home it between providers without renumbering. The traffic behind a municipal /24 like this is city-hall infrastructure, public-facing city services and staff connectivity, not residential subscribers.

Notable

The one announced prefix registers to CITYOFGOLDEN-IPV4-01, the city's own ARIN handle, so holder and registrant agree and there is nothing leased or brokered in the inventory.

Interesting

Despite the low AS number, this is not a 1990s allocation. ARIN registered the org record in October 2019 and the ASN itself in February 2020, and the announced 23.161.120.0/24 sits in modern ARIN space rather than the legacy swamp. AS11004 is a recycled number: it was returned by whoever held it before and reissued to Golden, so its number says nothing about the age of the network behind it.